Move old parser into matcher package

This is the first of two commits that removes matchers from the
deprecated pkg/labels package and into the new matcher package.
It moves the old regex parser that is known as classic mode
into a package called oldparse. This package will be deleted
in future when classic mode is removed.

Signed-off-by: George Robinson <[email protected]>

matcher/compat/parse.go

@@ -24,6 +24,7 @@ import (
 	"github.com/prometheus/common/model"
 
 	"github.com/prometheus/alertmanager/featurecontrol"
+	"github.com/prometheus/alertmanager/matcher/oldparse"
 	"github.com/prometheus/alertmanager/matcher/parse"
 	"github.com/prometheus/alertmanager/pkg/labels"
 )
@@ -77,7 +78,7 @@ func InitFromFlags(l log.Logger, f featurecontrol.Flagger) {
 func ClassicMatcherParser(l log.Logger) ParseMatcher {
 	return func(input, origin string) (matcher *labels.Matcher, err error) {
 		level.Debug(l).Log("msg", "Parsing with classic matchers parser", "input", input, "origin", origin)
-		return labels.ParseMatcher(input)
+		return oldparse.ParseMatcher(input)
 	}
 }
 
@@ -86,7 +87,7 @@ func ClassicMatcherParser(l log.Logger) ParseMatcher {
 func ClassicMatchersParser(l log.Logger) ParseMatchers {
 	return func(input, origin string) (matchers labels.Matchers, err error) {
 		level.Debug(l).Log("msg", "Parsing with classic matchers parser", "input", input, "origin", origin)
-		return labels.ParseMatchers(input)
+		return oldparse.ParseMatchers(input)
 	}
 }
 
@@ -124,7 +125,7 @@ func FallbackMatcherParser(l log.Logger) ParseMatcher {
 		// Parse the input in both parsers to look for disagreement and incompatible
 		// inputs.
 		nMatcher, nErr := parse.Matcher(input)
-		cMatcher, cErr := labels.ParseMatcher(input)
+		cMatcher, cErr := oldparse.ParseMatcher(input)
 		if nErr != nil {
 			// If the input is invalid in both parsers, return the error.
 			if cErr != nil {
@@ -155,7 +156,7 @@ func FallbackMatchersParser(l log.Logger) ParseMatchers {
 		// Parse the input in both parsers to look for disagreement and incompatible
 		// inputs.
 		nMatchers, nErr := parse.Matchers(input)
-		cMatchers, cErr := labels.ParseMatchers(input)
+		cMatchers, cErr := oldparse.ParseMatchers(input)
 		if nErr != nil {
 			// If the input is invalid in both parsers, return the error.
 			if cErr != nil {

pkg/labels/parse.go → matcher/oldparse/parse.go

@@ -11,24 +11,26 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package labels
+package oldparse
 
 import (
 	"fmt"
 	"regexp"
 	"strings"
 	"unicode/utf8"
+
+	"github.com/prometheus/alertmanager/pkg/labels"
 )
 
 var (
 	// '=~' has to come before '=' because otherwise only the '='
 	// will be consumed, and the '~' will be part of the 3rd token.
 	re      = regexp.MustCompile(`^\s*([a-zA-Z_:][a-zA-Z0-9_:]*)\s*(=~|=|!=|!~)\s*((?s).*?)\s*$`)
-	typeMap = map[string]MatchType{
-		"=":  MatchEqual,
-		"!=": MatchNotEqual,
-		"=~": MatchRegexp,
-		"!~": MatchNotRegexp,
+	typeMap = map[string]labels.MatchType{
+		"=":  labels.MatchEqual,
+		"!=": labels.MatchNotEqual,
+		"=~": labels.MatchRegexp,
+		"!~": labels.MatchNotRegexp,
 	}
 )
 
@@ -52,8 +54,8 @@ var (
 //	statuscode=~"5.."
 //
 // See ParseMatcher for details on how an individual Matcher is parsed.
-func ParseMatchers(s string) ([]*Matcher, error) {
-	matchers := []*Matcher{}
+func ParseMatchers(s string) ([]*labels.Matcher, error) {
+	matchers := []*labels.Matcher{}
 	s = strings.TrimPrefix(s, "{")
 	s = strings.TrimSuffix(s, "}")
 
@@ -114,7 +116,7 @@ func ParseMatchers(s string) ([]*Matcher, error) {
 // character). However, literal line feed characters are tolerated, as are
 // single '\' characters not followed by '\', 'n', or '"'. They act as a literal
 // backslash in that case.
-func ParseMatcher(s string) (_ *Matcher, err error) {
+func ParseMatcher(s string) (_ *labels.Matcher, err error) {
 	ms := re.FindStringSubmatch(s)
 	if len(ms) == 0 {
 		return nil, fmt.Errorf("bad matcher format: %s", s)
@@ -174,5 +176,5 @@ func ParseMatcher(s string) (_ *Matcher, err error) {
 		return nil, fmt.Errorf("matcher value contains unescaped double quote: %s", ms[3])
 	}
 
-	return NewMatcher(typeMap[ms[2]], ms[1], value.String())
+	return labels.NewMatcher(typeMap[ms[2]], ms[1], value.String())
 }